Horizontal wrapper with a side seal attachment

ABSTRACT

A continuously operating machine is provided for wrapping articles with a heat shrinkable plastic film automatically and sequentially. Articles are continuously, transferred along a horizontal pathway to a plurality of processing stations. At a first station, articles are tubularly overwrapped and sealed along a side edge thereof with excess film material being automatically trimmed away. Next, the articles are separated one from the other at a second station and at a last succeeding station, the resulting wrapped articles are subjected to thermal film shrinking. The side seal and trim apparatus includes a heat seal and trim unit which engages free side edges of the film tube to one another and trims excess away, the unit being sandwiched between drive and alignment members.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.791,659, filed Nov. 12, 1991, and titled "SHRINK FILM WRAPPING MACHINE".This application was subsequently refiled as a File Wrapper ContinuingApplication on Oct. 12, 1993, now U.S. Ser. No. 08/135,136, which hasissued as U.S. Pat. No. 5,371,999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an improved horizontal packaging machine, orwrapper, especially a continuously operating machine for wrappingarticles with a heat shrinkable plastic film or the like automaticallyand sequentially, and producing a side sealed, trimmed package for eacharticle.

2. Description of the Prior Art

Various packaging machines for wrapping materials automatically andsequentially with heat shrinkable film are available commercially fromvarious manufacturers. However, these machines do not offer anattachment or unit for creating a side seal which is trimmed as it isformed, creating a further benefit of keeping heat from the sealingstation away from articles being packaged.

The art needs a new and improved wrapping machine which is adapted foruse with heat shrinkable wrapping film and which has a new and improvedside seal attachment or unit providing the described advantages andwhich has simplified configuration, adjustments and operationalfeatures.

SUMMARY OF THE INVENTION

This invention relates to a continuously operating package wrappingmachine for shrink film and the like which automatically andsequentially wraps packages with a plastic film or the like, and to amethod for accomplishing same. The machine and the method each utilize asuccessive combination of a wrapping station, a side seal and trimstation, a package separating station and a film shrink station.

The invention relates to a new and very useful side seal and trimstation attachment or unit for a sequence of longitudinally wrappedpackages and to a method for continuously and sequentially side sealingand trimming each wrapped and continuously advancing package of thepackage sequence.

The method of the invention can be practiced at surprisingly highpackage unit operating rates.

Other and further aspects, objects, aims, features, advantages,applications, variations, embodiments, and the like will be apparent tothose skilled in the art from the present specification taken with theaccompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial diagrammatic side elevational view of one embodimentof a shrink film wrapping machine of this invention;

FIG. 2 is a perspective view of a forward end of the machine of FIG. 1;

FIG. 3 is an enlarged, detailed view of the side seal and trim stationand unit;

FIG. 4 is an enlarged perspective view showing apparatus componentsforming the apparatus at the station in a functional mode thereof;

FIG. 5 is an enlarged perspective view showing unit components in anonfunctional mode thereof;

FIG. 6 is an enlarged side view of the unit showing vertical andhorizontal adjustability thereof;

FIG. 7 is a rear view of the unit showing a synchronized chain drivethereof;

FIG. 8 is a top plan view of a top jaw of the unit;

FIG. 9 is a top plan view of a bottom jaw of the unit;

FIG. 10 is an exploded side view of a heat seal head of the unit;

FIG. 11 is a perspective view of a heat seal head of the heat seal unitand is taken along line 11--11 of FIG. 10;

FIG. 12 is a longitudinal cross section through the heat seal unit ofFIG. 10;

FIG. 13 is a simplified block diagram of the electrical system used foroperative control of the side seal and trim unit in conjunction withthat of the shrink wrap machine.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to the Figures in greater detail there is illustrated thereina section of one embodiment of a shrink film wrapping machine of thepresent invention designated in its entirety by reference numeral 20.

In machine 20, packages, articles or objects that are being wrappedcontinuously and sequentially are moved horizontally along a conveyorpathway which extends through three successive stationary processingstations 24, 25 and 26. Thus, a plurality of similarly sized objectswhich are to be individually wrapped by machine 20 with a heatshrinkable film 27 (FIG. 2) are sequentially deposited upon the inputend of a endless conveyor 22, conveyor 22 continuously operating andadvancing to the left in FIG. 1, moving to the first processing station24.

First processing station 24 is provided for longitudinally andcontinuously overwrapping successive objects with a film overwrap 27having a tubular configuration. The tube center region encompasses thearticles therein which are to be sealed into packages.

Thus, as each object moves through station 24, it becomes wrapped in amanner where free side edges 28 of the film 27 to be sealed to oneanother meet and lie along a side edge 30 of the articles 32. The film27 is preferably comprised of a thermally shrinkable polymeric material.

In station 24, free opposite side edges 28 of the film tube 27' arebrought together by a plow arrangement 34 so that the edges 28 lie alongthe side edge 30 of the articles 32 being wrapped. The edges 28 are thenthermally interfacially bonded together so as to hold the coplanar edgesof the formed film tube 27' closed and together with material excess 36being cut away to form a clean side seal at 37.

As each thus wrapped article 32 leaves station 24, it is engaged by acontinuously advancing conventional type vacuumized endless beltconveyor 38. Preferably, belt conveyor 38 is provided with a pluralityof closely spaced apertures 39 that extend therethrough. Thus, thewrapped articles 32 are held in fixed position relative to one anotherupon an upper surface of belt conveyor 38. Also the vacuum provides theforce to pull and move the wrapped articles 32 from station 24 to thenext processing station 25.

From a tail end of belt conveyor 38, each object is transferred to aconveyor 42 which commences in adjacent, longitudinally spacedrelationship to belt conveyor 38. Conveyor 42 moves objects 21continuously through station 25 wherein a cross head sealer and cutter40 operates continuously.

In cross head sealer and cutter 40 operation, first a forward end of thetube surrounding each article 32 is cut and heat fused. Then, as eachresulting individual article 32 continues its advance on the beltconveyor 42 the rearward or trailing end of each such bag being formedis cut and heat fused, thereby completing formation of a packaging bagabout each article 32.

The cutting and heat fusing preferably takes place along a line whichextends transversely across the belt conveyor 42 and is mid-way betweeneach pair of successive longitudinally spaced article 32 on the beltconveyor 42. Preferably also, this line is mid-way between the top andthe bottom ends of each pair of successive articles 32.

From station 25 and belt conveyor 42, each now completely bagged article32 is advanced and is transferred to an endless belt off-feed transferconveyor 44 which is longitudinally spaced from but in adjacentrelationship with belt conveyor 42. Conveyor 44 in embodiment 20 is alinking conveyor which functions to deliver wrapped and sealed articles32 to a station 26 where a continuously operating shrink tunnel 45 issituated. Each article 32 emerging from tunnel 45 is completely packagedwithin a heat shrunk side sealed, trimmed film package.

Packaged articles 32 upon reaching the end (not shown) of belt conveyor44 are collected for storage, subsequent further bulk packaging,shipment, or the like, as desired.

The machine 20 incorporates a drive subsystem 48 which causes theconveyors, the film wrapper, the side seal and trim unit 50 at station24, and the cross head sealer and cutter 40 at station 25 to operatesynchronously with each other. The drive subsystem 48 is illustrated inFIG. 1 and is described in detail in U.S. patent application Ser. No.791,659, the teachings of which are incorporated herein by reference.

Turning now particularly to FIGS. 2-12, there is illustrated therein thestation 24 incorporating therein the novel side seal and trimming unit50 made in accordance with the teachings of the present invention.

As shown, the side seal and trim unit 50 is incorporated immediatelyadjacent the plow arrangement 34 where the film 27 fed from a 52 rollthereof is placed about consecutively supplied articles in the form of acontinuous tube 27', with free side edges 28 of the film beingapproximated along a longitudinal side edge 30 of the articles 32therewithin.

By creating a side seal rather than the commonly formed seal which liesover one surface of the article 32 to be packaged, heat need not beapplied against the article 32.

Rather the heat seal and trimming unit 50 is herein proposed whichcreates a seal alongside, rather than upon the articles 32. The unit 50,as will be described in greater detail hereinafter, not only creates aneat, precise side seal, but trims away excess edge area of the film 27beyond the seal so that a neat, packaged article 32 is produced.

It is seen from FIGS. 3-9 that the unit 50 includes two jaws 54 and 56,the first jaw 54 being a top or upper jaw 54, and the second being abottom or lower jaw 56, the jaws 54 and 56 being separable from eachother toward a trailing edge 58 thereof by a small pneumatic piston andcylinder arrangement 60.

It will be seen that a forward end 62 of the jaws 54 and 56 is hinged,with the hinged end 62 being particularly configured to maintain a firstset of alignment and drive members 64 adjacent the end 62 abutting atall times. To provide such maintained abutment even when the jaws 54 and56 are disengaged, the jaws 54 and 56 are each provided with acorresponding ramped surface portion 66 which creates a relief when thetop jaw 54 tilts, thus maintaining the drive members 64 adjacent oneanother.

Proximal to these drive members 64 is a heat sealing and cutting head 70which is mounted on the top jaw 54 and which coacts with a cooperatingrotating base member 72 therebeneath against which the head 70 seatswhen the jaws 54 and 56 are approximated.

This base member 72 incorporates a circumferential area 74 thereon whichis made of a thermally insulating material. Thus, when film 27 isengaged between the head 70 and the insulated base 72, it is sealed byheat generated within the head 70 and trimmed against the insulated basearea 74.

Next on the unit 50 follows a second pair of drive and alignment members80 which are similar to the first pair 64. Here because empiricaltesting has shown that the heated area of the film 27 is notsufficiently cooled and may stick to the members 80, the upper member80' is circumferentially slotted at 82, allowing for some relief andsignificantly decreasing, if not altogether eliminating potentialjamming of the hot film in the area of the seal between the drivemembers 80 and 80'.

The drive members 64 and 80 comprise cylindrical wheel elements whichare shaft mounted, the toothed gear shafts 90 being synchronouslyengaged on each jaw 54 and 56 by a drive chain 92 on a back side 94 ofthe unit 50 as shown in FIG. 7.

This drive system is driven by a secondary chain drive 95 whichoriginates from a drive shaft 100 which also synchronizes operation ofthe other units 25 and 26 of the machine 20.

Thus, when one unit speeds up or slows down, the other units follow.

Obviously, articles 32 to be packaged come in various sizes.

To accommodate articles of various thickness and width the unit 50 mustbe moveable, both in the vertical and horizontal planes.

In this respect, as best shown in FIG. 6, the unit 50 rides on aplatform 110 which is a horizontally moveable toward and away from theadjacent conveyor 22 upon which the articles 32 are carried, thusaccommodating narrow as well as wider articles 32. The platform 110 isengaged to a threaded horizontal shaft 112 along which it can be movedin a known manner.

Further, the unit 50 is carried upon a threaded vertical shaft 120 whichextends upwardly from the platform 110. Upon this shaft 120, the heightof the unit 50 can be easily be adjusted to accommodate thick as well asthinner articles 32 to consistently provide a centered side sealtherealong.

To maintain alignment of the jaws 54 and 56 at all times, two alignmentrods 124 and 126 are provided, extending upwardly through end ports 128and 130 respectively in the bottom jaw 56, from their source on theplatform 110. The bottom jaw 56 is thus maintained aligned relative tothe conveyor 22 at all times, with the upper jaw 54 being maintainedaligned therewith by the method of engagement therebetween.

In this respect, as defined earlier, the one end 62 of the jaws 54 and56 is pivotably hinged together while the opposite end 58 incorporatesthe hydraulic arrangement 60 for causing disengagement and pressurizedengagement at the end 58.

As also stated before, the leading drive members 64 are at all timesmaintained engaged. Such maintained engagement is preferred, so that, ifa shut down is ever necessary, the free side edges 28 of film 27 willnot come out of alignment, and the unit 50 can simply have the jaws 54and 56 reengage after shutdown, with the unit 50 becoming once againfunctional without the necessity of refeeding the film 27 thereinto.

It will further be understood that the rotatable members 64 and 80'mounted on the upper jaw 54 are driven upon the pressurized engagementbetween the trailing drive members 80 and 80' on the jaws 54 and 56.

Thus, when the jaws 54 and 56 are separated, rotation of all elementsceases until the jaws 54 and 56 are locked back together, with thepressure developed between the trailing drive members 80 and 80' by thehydraulic arrangement 60 once again driving all the members.

To accommodate the stress created by being driven members, the trailingdrive members 80 and 80' are bearing 130 mounted.

Obviously, all drive members are made of a highly frictional material,such as rubber.

Turning now to a more detailed study of the heat sealing and cuttinghead 70, the head 70 will be seen to be mounted on a hollow rotatableshaft 132 through which electrical wiring 134 can be run to the heatedhead 70. Obviously since the head 70 and shaft 132 are rotatable, arotary electrical connection (not shown) of known type must be used sothat twisting of the wiring 134 does not occur.

The electrical wiring 143 engages a circular ceramic heater element 136seated within the heater head 70, the head 70 being comprised of twodish shaped members 140 and 142 which, when joined together in asuitable manner form a pointed circumferential edge 150 which shearsthrough the film 27 fed therebeneath, with the heat extending toward thearticle 32 and sealing an adjacent area of the film at 37.

To produce a clean cut and to accommodate temperatures in the range of300°-400° F. it is preferred to form the head 70 of stainless steel,which may be coated with an insulating and slick material such aspolytetrafluoroethylene. Also, as is known, means 150 for temperaturecontrol may be incorporated to accommodate various types of film 27.

Turning back to FIG. 3 briefly, it will be seen that an optional vacuumsystem 160 may be provided downstream of the unit 50 to collect the cutoff film material, if desired.

In FIG. 13 is shown the diagrammatic representation of the machinecontrol system 200 including controls for the side seal and trim unit50.

As shown, the hydraulic system 60 for opening and closing the unit 50 isoperated by a solenoid 210 from a motor control board 212 for themachine 20 in a manner where the jaws 54 and 56 of the unit 50 areopened whenever a motor 220 powering the machine 20 stops.

A timer 222 for the unit 50 is further provided which is incommunication with the motor control board 212 as well and causes thejaws 54 and 56 to reengage, via solenoid valve 210 activation, justbefore motor 220 start up so that the film 27 is already firmly grippedbetween the jaws 54 and 56 at motor 220 engagement, with no slack beingformed in the film 27, which could cause problems, such as folds oroverrun of film 27 in certain areas of the seal being formed at 37.

Obviously, temperature of the heat head 70 and operation thereof arealso controlled by the machine control system 200.

As described above, the machine 20 and side seal and trim unit 50thereof provide a number of advantages, some of which are describedabove and others of which are inherent in the invention.

Also, modifications may be proposed without departing from the teachingsherein. Accordingly the scope of the invention is only to be limited asnecessitated by the accompanying claims.

We claim:
 1. Apparatus for continuously wrapping articles comprising:(a)conveyor means for transporting a plurality of like articles along agenerally horizontal path with predetermined spacing betweenlongitudinally adjacent successive articles; (b) a first station alongsaid path having means for continuously forming a longitudinallyextending tubular overwrap circumferentially about said articles from acontinuous film as said articles pass through said station and includingmeans for adhering together free side edge portions of said overwrap inan area alongside each of said articles and trimming away excess film;(c) a second station along said path having means for cross sealing andseparating said tubular overwrap between adjacent successive articles,and (d) a third station along said path having means for subjecting eachsaid successive separately packaged article to predetermined elevatedtemperatures so that said film is heat shrunk about each said article,said first station comprises a side seal and trim unit which isvertically and horizontally adjustable to rest alongside articlespassing through said station, a seal mechanism thereof beingapproximately centered along a thickness of the articles, said side sealand trim unit is comprised of two jaws, one being a lower jaw, the jawsbeing hingedly fixed to one another at a leading end thereof and beingseparable at a trailing end thereof, the trailing ends of the jaws beingengaged to one another by a hydraulic piston and cylinder arrangement.2. The apparatus of claim 1 wherein each of said jaws has engagedthereon a first alignment and drive wheel, a section of a rotatable heatsealing and cutting assembly, and a second alignment and drive wheel. 3.The apparatus of claim 2 wherein said second alignment and drive wheelon said lower jaw is actively driven and drives, by means of a drivechain engagement, said first alignment and drive wheel and said sectionof said rotatable heat sealing and cutting assembly mounted on saidlower jaw.
 4. The apparatus of claim 3 wherein said second alignment anddrive wheel on said lower jaw frictionally engages against and drivessaid second alignment and drive wheel on said upper jaw.
 5. Theapparatus of claim 4 wherein said second alignment and drive wheel onsaid upper jaw drives, by means of drive chain engagement, said firstalignment and drive wheel and said section of said rotatable heatsealing and cutting assembly mounted on said upper jaw.
 6. The apparatusof claim 5 wherein said wheels and said rotatable heat sealing andcutting assembly are all synchronously driven by said drive chains whensaid jaws are functionally engaged to one another.
 7. The apparatus ofclaim 6 wherein said first alignment and drive wheels on said upper andlower jaws are constantly maintained engaged.
 8. The apparatus of claim7 wherein each of said jaws at the hinged end thereof has a rampedabutment surface which maintains abutment of the hinged end of said jawswhen the opposite ends of said jaws are separated from one another. 9.The apparatus of claim 8 wherein said section of said heat sealing andcutting assembly mounted on said lower jaw comprises a rotatable basemember in the form of a wheel having a circumferential portion thereofmade of an insulating material, and cutting assembly mounted on saidupper jaw comprises a heater head which is rotatably mounted by a meansof a hollow shaft, the heater head including a ceramic heat elementtherein, having a configuration to produce a circumferential tip beingpositioned to engage against said circumferential portion of said basemember which is made of insulating material.
 10. Apparatus forcontinuously wrapping articles comprising:(a) conveyor means fortransporting a plurality of like articles along a generally horizontalpath with predetermined spacing between longitudinally adjacentsuccessive articles; (b) a first station along said path having meansfor continuously forming a longitudinally extending tubular overwrapcircumferentially about said articles from a continuous film as saidarticles pass through said station and including means for adheringtogether free side edge portions of said overwrap in an area alongsideeach of said articles and trimming away excess film; (c) a secondstation along said path having means for cross sealing and separatingsaid tubular overwrap between adjacent successive articles, and (d) athird station along said path having means for subjecting each saidsuccessive separately packaged article to predetermined elevatedtemperatures so that said film is heat shrunk about each said article,said first station comprises a side seal and trim unit which isvertically and horizontally adjustable to rest alongside articlespassing through said station, and a seal mechanism thereof beingapproximately centered along a thickness of the articles, said side sealand trim unit being comprised of two jaws, one being a lower jaw, thejaws being hingedly fixed to one another at one end thereof and beingseparable at an opposite end thereof, and means for selectively closingand opening the separable opposite ends of the jaws.
 11. The apparatusof claim 10 wherein each of said jaws has engaged thereon a firstalignment and drive wheel, a section of a rotatable heat sealing andcutting assembly, and a second alignment and drive wheel.
 12. Theapparatus of claim 11 wherein said second alignment and drive wheel onsaid lower jaw is actively driven and drives, by means or a drive chainengagement, said first alignment and drive wheel and said section ofsaid rotatable heat sealing and cutting assembly mounted on said lowerjaw.
 13. The apparatus of claim 12 wherein said second alignment anddrive wheel on said lower jaw frictionally engages against and drivessaid second alignment and drive wheel on said upper jaw.
 14. Theapparatus of claim 13 wherein said second alignment and drive wheel onsaid upper jaw drives, by means of drive chain engagement, said firstalignment and drive wheel and said section of said rotatable heatsealing and cutting assembly mounted on said upper jaw.
 15. Theapparatus of claim 14 wherein said wheels and said rotatable heatsealing and cutting assembly are all synchronously driven by said drivechains when said jaws are functionally engaged to one another.
 16. Theapparatus of claim 11 wherein said first alignment and drive wheels onsaid upper and lower jaws are constantly maintained engaged.
 17. Theapparatus of claim 12 wherein said section of said sealing and cuttingassembly mounted on said lower jaw comprises a rotatable base member inthe form of a wheel having a circumferential portion thereof made of aninsulating material, and cutting assembly mounted on said upper jawcomprises a heater head which is rotatably mounted by a means of ahollow shaft, the heater head including a ceramic heat element therein,having a configuration to produce a circumferential tip being positionedto engage against said circumferential portion of said base member whichis made of insulating material.
 18. The apparatus of claim 10 whereinsaid jaws at the hinged end thereof has a ramped abutment surface whichmaintains abutment of the hinged end of said jaws when the opposite endsof said jaws are separated from one another.
 19. Apparatus forcontinuously wrapping articles comprising:(a) conveyor means fortransporting a plurality of like articles along a generally horizontalpath with predetermined spacing between longitudinally adjacentsuccessive articles; (b) a first station along said path having meansfor continuously forming a longitudinally extending tubular overwrapcircumferentially about said articles from a continuous film as saidarticles pass through said station and including means for adheringtogether free side edge portions of said overwrap in an area alongsideeach of said articles and trimming away excess film, said first stationcomprises a side seal and trim unit which is vertically and horizontallyadjustable to rest alongside articles passing through said station, aseal mechanism thereof being approximately centered along a thickness ofthe articles; and (c) a second station along said path having means forcross sealing and separating said tubular overwrap between adjacentsuccessive articles; (d) said side seal and trim unit being comprised oftwo jaws, one being a lower jaw, the jaws being hingedly fixed by ahinge to one another at one end thereof and being separable at anopposite end thereof, and means moving the jaws on said hinge forselectively closing and opening the separable opposite ends of the jaws,the jaws being positioned so as to extend generously at right angles tosaid means for cross sealing and separating said tubular overwrapbetween adjacent successive articles.
 20. The apparatus of claim 19wherein each of said jaws has engaged thereon a first alignment anddrive wheel, a section of a rotatable heat sealing and cutting assembly,and a second alignment and drive wheel.
 21. The apparatus of claim 20wherein said second alignment and drive wheel on said lower jaw isactively driven and drives, by means of a drive chain engagement, saidfirst alignment and drive wheel and said section of said rotatable heatsealing and cutting assembly mounted on said lower jaw.
 22. Theapparatus of claim 21 wherein said second alignment and drive wheel onsaid lower jaw frictionally engages against and drives said secondalignment and drive wheel on said upper jaw.
 23. The apparatus of claim22 wherein said second alignment and drive wheel on said upper jawdrives, by means of drive chain engagement, said first alignment anddrive wheel and said section of said rotatable heat sealing and cuttingassembly mounted on said upper jaw.
 24. The apparatus of claim 23wherein said wheels and said rotatable heat sealing and cutting assemblyare all synchronously driven by said drive chains when said jaws arefunctionally engaged to one another.
 25. The apparatus of claim 20wherein said first alignment and drive wheels on said upper and lowerjaws are constantly maintained engaged.
 26. The apparatus of claim 21wherein said section of said sealing and cutting assembly mounted onsaid lower jaw comprises a rotatable base member in the form of a wheelhaving a circumferential portion thereof made of an insulating material,and cutting assembly mounted on said upper jaw comprises a heater headwhich is rotatably mounted by a means of a hollow shaft, the heater headincluding a ceramic heat element therein, having a configuration toproduce a circumferential tip being positioned to engage against saidcircumferential portion of said base member which is made of insulatingmaterial.
 27. The apparatus of claim 19 wherein said jaws at the hingedend thereof has a ramped abutment surface which maintains abutment ofthe hinged end of said jaws when the opposite ends of said jaws areseparated from one another.